Effect of absorption on the X-ray spectrum. Top panel: energy dependence of the absorption spectrum. The unabsorbed spectrum is defined as F_v = v⁻². The labeled lines show column densities matching the contours in Fig. 7. Bottom panel: effect of N_HI on the broadband flux. The vertical lines show the threshold at which F_v decreases by a factor of the unabsorbed value in the same band.